They are smaller than mosquitoes by a lot, but their bite can be just as annoying. And this fall, it seems, these little critters are more numerous than ever.

Minute pirate bugs and their close cousin, insidious flower bugs, belong to the group of bugs known as true bugs, which include bed bugs, squash bugs and stink bugs.

Despite their propensity to bite, these bugs, which are about an eighth of an inch, are not closely related to skeeters, but about as far removed from them as humans from kangaroos, said Armin Moczek, a professor of biology at Indiana University.

What ties together the so-called true bugs is a characteristic that you might already have noticed if you’ve been outside in an area where these guys are abundant.

“All those have piercing, sucking mouth parts, where they either suck plant juices or juices from live prey,” Moczek said.

Unlike mosquitoes, though, these guys are not after your blood.

In fact, most of the year they show limited interest in humans for the most part, experts say.

Toward the end of summer and in early fall — as the first frost and the bugs' demise approaches — they do tend to start bothering us. Experts say that they are unsure why these bugs start biting now, but they may be more likely to bite when their population density is high, Moczek said.

“They have small little strawlike mouth parts, and what they do is they probe things to determine whether or not things are edible. They typically feed on plants but also other small insects,” said John Obermeyer, an integrated pest management specialist at Purdue University. “Then this time of year for some reason they will land on people, and they will poke them.”

Once they determine that the human is not something more scrumptious like an aphid, one of their preferred meals, they move on.

These bugs are so fond of aphids that they are actually commercially available for use in greenhouses to control the proliferation of those pests, Moczek said. About twice the size of the aphid, the minute pirate bugs stick their beaks into their prey and suck it dry.

As long as you’re not an aphid, you should be fine if one of these guys gets you. Unlike mosquitoes and ticks, they don’t carry diseases.

And for the most part, as Moczek notes, the humans win when the bugs interact with us.

“They bite us. We see them. We squish them,” he said.

Call IndyStar reporter Shari Rudavsky at (317) 444-6354. Follow her on Twitter and on Facebook.